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Perlisten speakers

Matthew J Poes

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I believe the S4B bookshelves MSRP for around $7,000 a pair which is a bit more than the $4,000 Revel M126Be but the S4B is 3-way with that impressive beamforming technology in its MTM tweeter array while the M126Be is a 2-way, both with beryllium tweeters. Neither the Perlisten nor Revel bookshelves are very efficient at 85 dB and 86 dB, respectively.

the Perlisten should be able to play a good bit louder. Of course, it will need a ton of power to accomplish that feat. About 400 watts.
 

richard12511

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so I actually have the same question about the S4s myself.

first, as noted a moment ago, there is more to the spec than just output and distortion. Directivity, response, and bandwidth all matter too. It’s different from the old spec as well.

I also know that all the subs other than the single 12 can meet the Dominus bass spec as a single. But the single 12 requires two. This is not unusual for THX to allow subs to pass in multiples.

I’ll find out why the smaller speakers appear to fail the requirements made public but get a certificate. There might be different requirements for certain types?

Maybe different requirements for mains/surrounds? Maybe the pass as "surrounds".
 

richard12511

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these have every bit as much bass as the Revel F328Be and Amir indicated that speaker had plenty of output. Everyone who has heard them without subs has been surprised by how good the bass is. I think it makes little sense to criticize the bass bases on a single measurement that seems to be misinterpreted.

Could Gene do a side by side measurement with the F328Be to see what the extension difference looks like? I think that would be a great way to tell.
 

hardisj

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About most speakers becoming tweeter limited, I didn't know this, but I can see now how it changes things. I actually always thought the opposite.

To date, I have fried way more woofer voice coils than I have tweeters.
there is a lot more to the spec than just output. That is only one part of it. Their response shape, bandwidth, and directivity must also meet the spec. While this was always true to some extent, the Dominis spec is more stringent and different. So while lots of speakers will play louder, they may not pass the tests anyway.

Is the specification actually available? The THX site doesn't supply their definitions and all I can find is this:

It’s been a challenging year not going to the movies, so THX is excited to announce we’re bringing the cinematic experience to your home theaters with THX Certified Dominus.

Dominus is the newest and the largest performance class of THX Certification, meant to bridge the gap between large home theater speakers and those used in movie houses worldwide. Home theater owners with rooms up to 184 cubic meters of space and up to a 6-meter viewing distance (or up to 6500 cubic feet and up to 20 feet, respectively) can fill their entertainment space with the superior audio quality they expect from THX Certified products.

That means quieter whispers, bigger booms, and everything in-between at a greater distance.

G54qKC3hcK0xpGPF3YY9LwKKq-0mAaEHRzf9Ipeso7w9DlSG11TZEGCLu24wCGpB8v5n_nvf7fSM9kEzYImyu40O1ogxr1Li3uidiRVsjilAnalnOFnLafMtGbHund--Unpv56fg

Yes, we developed the THX Certified Dominus performance class to fill the most extensive home theaters with sound, but since we’re THX, these new speakers need to be more than just loud. During our rigorous testing process, we pay special attention to distortion levels at high volumes. And with Dominus, we push this to the extreme, subjecting these speakers to 120 dB sound pressure levels where they must keep distortion to a minimum. Dominus speakers must also be sensitive enough to reach the cinematic THX Reference Level with THX Certified Dominus and certain THX Certified Ultra power amplifiers. We’re happy to report that the 92 dB sensitivity requirement for THX Certified Dominus loudspeakers is the most sensitive of any THX loudspeaker category.

The result of the THX Certified Dominus performance class is beastly speakers that produce a massive wall of sound that’ll immerse everyone in your theater or hi-fi listening room, no matter where they’re sitting, with beautiful, distortion-free sound.


Then I found this flyer-type thing:
https://static1.squarespace.com/sta...03331620257/THX_Dominus+One+Sheet10.21[1].pdf

And this link which basically just says the exact same thing:
https://www.soundandvision.com/cont...ified Dominus,to the primary seating position.

1621988215163.png





There are all these vague descriptors. For example:
"play loudly without fatigue" - What does this mean?
"a flat frequency response " - Define "flat".
"must pass strict distortion requirements" - And those requirements are ... ?
"they have good off-axis response" - Define "good".

I see two actual specs. And one isn't even a spec; it is 120dB with "very low distortion" (um, what is the definition?).
They do also spec 92dB sensitivity. So, they at least tell us that.

TBH this kind of stuff is just annoying to me. It reads more like marketing than actual specifications. They (THX) should let the customer know exactly what the standards are if they are going to make such a big deal about them.
 

Matthew J Poes

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Could Gene do a side by side measurement with the F328Be to see what the extension difference looks like? I think that would be a great way to tell.
For sure. I’ll do that once they come in. I quite literally have a mic designed to measure earthquakes. It is flat to .5hz with a NIST certified lab report. I’ll measure them both once we have them setup.

I also would like to do some SPL/Distortion tests. Normally these are kind of bogus but given that both will be in the same room at the same time, they would highlight differences ok. I am curious to see if one plays louder with lower distortion down that low. I think the Perlisten will be better given what I know of the two. But proof would be in the measurements.

we could also consider sticking nearly $40k worth of speakers into his backyard and annoy his neighbors for some compression tests. Not sure he will be up for that. That would be a lot more definitive.

I have a whole white paper on the drivers in the F328Be. I am not allowed to share any of it. But just know that when I say my opinion, it’s coming from knowing the differences in the drivers. The Revel speakers are really good. But I know the Perlisten drivers spec a bit better I. Ways that would matter for bass.
 

hardisj

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I also would like to do some SPL/Distortion tests. Normally these are kind of bogus but given that both will be in the same room at the same time, they would highlight differences ok. I am curious to see if one plays louder with lower distortion down that low. I think the Perlisten will be better given what I know of the two. But proof would be in the measurements.

Be cautious about posting these. As you no doubt are aware, reflections are seen as distortion as well. So the absolute levels will probably cause people to make the wrong assumptions. I'd probably post process the data to simply show the differences between the different orders and keep it solely as "relative" rather than "absolute". And make sure you're in the far-field to capture the entire speaker response. NF measurements won't work for this. A 2m GP test would suffice. And super easy to do. Just my $0.02. :)


we could also consider sticking nearly $40k worth of speakers into his backyard and annoy his neighbors for some compression tests. Not sure he will be up for that. That would be a lot more definitive.

Long term and short term, please. It would be interesting to see what happens as the speaker elements heat up and a simple sweep at different levels only won't give us that kind of long term info.


The Revel speakers are really good. But I know the Perlisten drivers spec a bit better I. Ways that would matter for bass.

I'd be curious to know what the linear xmax is (not the mechanical xmax, but the actual IEC 62458 standard definition), if you can provide that information.
 

Matthew J Poes

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To date, I have fried way more woofer voice coils than I have tweeters.


Is the specification actually available? The THX site doesn't supply their definitions and all I can find is this:




Then I found this flyer-type thing:
https://static1.squarespace.com/static/5e9e07f9cb66310d7c7e93df/t/5f90e624585dd565cc31ac4e/1603331620257/THX_Dominus+One+Sheet10.21[1].pdf

And this link which basically just says the exact same thing:
https://www.soundandvision.com/content/thx-certified-dominus-speaker-testing-glance#:~:text=The new THX Certified Dominus,to the primary seating position.

View attachment 131998




There are all these vague descriptors. For example:
"play loudly without fatigue" - What does this mean?
"a flat frequency response " - Define "flat".
"must pass strict distortion requirements" - And those requirements are ... ?
"they have good off-axis response" - Define "good".

I see two actual specs. And one isn't even a spec; it is 120dB with "very low distortion" (um, what is the definition?).
They do also spec 92dB sensitivity. So, they at least tell us that.

TBH this kind of stuff is just annoying to me. It reads more like marketing than actual specifications. They (THX) should let the customer know exactly what the standards are if they are going to make such a big deal about them.

I should have been more clear. When trying to designs. Speaker to meet the lofty 105dB max output, most done tweeters can’t do that. Most woofers can’t either. But you just add more. With tweeters, adding more just adds problems that need to be addressed. So on a lot of speakers it’s the tweeter that is holding it back from reaching thx rating. There is a reason so many THX speakers bad horn, waveguide, or tweeter arrays. It isn’t just directivity. It was also output. If I can get you in touch with Dan he can share more.

as for the THX spec, nope that is all that’s public. I’ve been to their headquarters in San Francisco, I’ve met with some of their guys, I had dinner with one of their executives, and I personally know two people who designed THX certified speakers. I still know as much as you. They all drop little hints here or there. But nobody has ever shared the real details that are needed.

what James and I have figured out is that the spec isn’t a joke or marketing. They just fail to share details. Every THX rated speaker or subwoofer we have measured has been better than average, with evidence of the THX requirements being a part of it. James noted that the THX rated subwoofers all passed their CEA-2010 tests with a lot less distortion. When we tested the Monoprice and Outlaw THX subs, we asked why the distortion was so low. It seemed to be due to limiters. We were told it was necessary to pass THX. So that implies they do set pretty strict distortion requirements. We don’t know what those thresholds are. We can only infer. When we did a little thought experiment comparing the 15” Monolith to the SVS PB16, it seemed like the SVS would lose its lowest passing result and you would need to subtract about 2-3 dB from each passing result to be at the same distortion limits imposed on the Monolith by THX.

I wish I knew more. I’ve honestly tried every trick in the book.
 

Matthew J Poes

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Be cautious about posting these. As you no doubt are aware, reflections are seen as distortion as well. So the absolute levels will probably cause people to make the wrong assumptions. I'd probably post process the data to simply show the differences between the different orders and keep it solely as "relative" rather than "absolute". And make sure you're in the far-field to capture the entire speaker response. NF measurements won't work for this. A 2m GP test would suffice. And super easy to do. Just my $0.02. :)




Long term and short term, please. It would be interesting to see what happens as the speaker elements heat up and a simple sweep at different levels only won't give us that kind of long term info.




I'd be curious to know what the linear xmax is (not the mechanical xmax, but the actual IEC 62458 standard definition), if you can provide that information.
For the Revel or the Perlisten? Perlisten is 8mm. I will double check, but they test drivers using the Klippel tester. So I assume it’s that spec. I’ll let you know.

Revel? I can’t tell you. I was given pretty strict orders not to share any of that information. So you have to go by my inferences.
 

Matthew J Poes

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Be cautious about posting these. As you no doubt are aware, reflections are seen as distortion as well. So the absolute levels will probably cause people to make the wrong assumptions. I'd probably post process the data to simply show the differences between the different orders and keep it solely as "relative" rather than "absolute". And make sure you're in the far-field to capture the entire speaker response. NF measurements won't work for this. A 2m GP test would suffice. And super easy to do. Just my $0.02. :)




Long term and short term, please. It would be interesting to see what happens as the speaker elements heat up and a simple sweep at different levels only won't give us that kind of long term info.

just annoy Gene. Tell him everyone wants to know!

mad for the in-room, I was thinking the 2m groundplane. I was hoping for the best. I wouldn’t share anything I didn’t have a modest amount of confidence in.

I also have Geddes software still which can do something similar with the distortion plots as NFS can. The only problem is that the LF model it uses is dramatically simplified to just 2 poles. So I am not totally sure that the Lf distortion is accurate with that. I would need to ask. Geddes didn’t really care about that when he wrote the software. His feeling was that the room dominates so who cares.
 

MZKM

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I’ve been to their headquarters in San Francisco, I’ve met with some of their guys, I had dinner with one of their executives, and I personally know two people who designed THX certified speakers. I still know as much as you.
The question is though, why? What possible reason is there for them to keep a certification requirement hidden? Obviously not actually asking you this, but just putting the question out there.
 

Matthew J Poes

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The question is though, why? What possible reason is there for them to keep a certification requirement hidden? Obviously not actually asking you this, but just putting the question out there.

well Laurie Fincham actually answered that fairly directly for me once. He said that the details of the specification are their IP. That when a company signs on to go through testing and obtain a certificate, it impacts the design of the speaker. They gain access to the knowledge of their engineers. If the specific specs were released then any company could copy the spec and charge less. Or a manufacturer could simply make their speaker meet the spec, claim it meets THX requirements, but not pay the fees necessary to support all their work. THX actually does a lot of research into what makes a system better and more enjoyable. Much like the Harman research. But it’s not public. They consider it all part of their IP.

I am not defending it or standing by it. Just sharing what I’ve been told.
 

Kachda

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The question is though, why? What possible reason is there for them to keep a certification requirement hidden? Obviously not actually asking you this, but just putting the question out there.
Edit: Deleted as Matthew answered this above
 

hardisj

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as for the THX spec, nope that is all that’s public. I’ve been to their headquarters in San Francisco, I’ve met with some of their guys, I had dinner with one of their executives, and I personally know two people who designed THX certified speakers. I still know as much as you. They all drop little hints here or there. But nobody has ever shared the real details that are needed.

Yea, it just befuddles me that it wouldn't be public information. And the cynic in me (which, honestly is pretty rare) is looking at this thinking "sure makes it easy for them to change the "spec" if a company is willing to pay for the tag"". Which, yes, that implies they are up to no good. And I don't really think they are. But if I have inklings of thoughts like that then I guarantee many are thinking things are much more sinister than that.


I wish I knew more. I’ve honestly tried every trick in the book.

I wonder if they'd be willing to tell Erin's Audio Corner - a new upstart loudspeaker manufacturer - how to achieve their Dominus Rex status. :D :p ;) :D

Jurassic_world_indominus_rex_v2_by_sonichedgehog2-d9j1f9q.png
 

hardisj

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just annoy Gene. Tell him everyone wants to know!

I'll stop by there on my way to Disney World and try to encourage him. :D


I also have Geddes software still which can do something similar with the distortion plots as NFS can.

What do you mean by this? Trying to make sure we are on the same page. The NFS doesn't do distortion, per se. It does, however, have the ability to use the anechoic response to create a room correction curve (per speaker, obviously, since ported/sealed/etc all disturb the room differently) and then you use that with the TRF module to make an in-room sweep and correct it with the ISC module. This is how I perform in-room measurements.
 

hardisj

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Perlisten is 8mm

That's quite good. But not industry-leading. Scanspeak 18wu is still the highest linear excursion 7-inch midwoofer I am personally aware of with 8.5mm one-way, limited by suspension (Bl is >10mm one-way). There is a newer brand whose name completely escapes me at the moment which is said to be higher per the same standard but I haven't verified that myself.

I wouldn't be surprised if Revels are lower, of course. Even though they dropped their affiliation with SB, the design is awful similar and the SB woofers are almost always rated at twice what the actual IEC standard specs them out. Aside from that, the 6.5-inch woofers in the F226Be speaker doesn't look to even have the ability - physically - to achieve that much linear excursion.
 

hardisj

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I live only a few minutes from him…

It was surreal news back last year when the first Covid case in our town was reported and I saw his name/face in the article.

Perfect! I'll pester him to do some tests and you can bring your excel sheets to provide some preference scores. Scale of 1-10 how much Gene would prefer us to leave his driveway.
 

BenB

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man expanding array has it such that there is a hard crossover with no significant overlap between the tweeter and mid ranges. Is that beamforming by any definition?

what your describing isn’t a crossover. There still must be overlap in output of the beamforming drivers or they can’t Interact with each other.

Hard crossover? Is that a technical term? David Smith put a lot of effort into determining how to place the speakers geometrically, and what order crossovers to use in order to create the dispersion pattern he was after. The results is a consistent Maximum Response Axis across the band of interest, with attenuated response at angles away from the MRA. That's a beam. He achieves this largely by using an array of multiple transmitters (aka beamforming). Compare the dispersion he achieves with his expanding arrays to a pair of full range drivers stacked vertically, and you'll see how important all the driver interactions are.
 

ctrl

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as was already noted, you have the wrong driver. They custom make their drivers. Each has about 8mm of one way excursion. That’s 16mm P-P linear excursion. Not sure how you figure that a single 10” subwoofer could exceed four 7” drivers with 8mm of excursion. That single 10” driver would need 18mm of linear xmax to equal these four drivers at 25hz.

Have calculated that very likely just like you. Okay, the SBAcoustics driver had 7.5'', the PerListen driver has only 7'' and a bit more linear excursion.

There is no problem to check my "calculation". A 7'' driver has a cone area of 130-150cm² - the thicker the surround, the smaller the cone area. So the 8mm excursion should rather require a thicker surround. Nevertheless, let's be generous and calculate with 145cm² cone area.

Vd = 4 x Sd x Xmax = 4 x 145cm² x 0.8cm = 464cm³

For comparison, let's consider the displacement volume Vd of 10'' subwoofer drivers.
One from the Dayton Reference series (mixture of sub and woofer) and one from the Ultimax series (pure subwoofer).

RSS265HO: Vd = 430cm³
UM10-22: Vd = 620cm³

Thus, the PerListen S7t has a displacement volume that is comparable to a 10'' subwoofer. With this comparison, I just want to prevent people from getting the wrong idea about what the speakers are capable of in terms of low frequency performance.

Update: Of course, you can doubt the manufacturer's specifications about Xmax. To be completely sure, you would have to measure all drivers yourself.
 
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